4
K. Kubiak-Wójcicka et al.
as waters of the Gulf of Gda´ nsk and ports bordering on territorial sea waters. The
length of the sea border is 440 km, which is 12.5% of the length of the state border
[1]. Almost 50% of the country’s surface is 100–200 m above sea level, while 3%
of the country’s surface is above 500 m amsl. The highest peak in Poland is Rysy
(2499 m amsl).
The most important elements of the hydrographic network in Poland are: rivers,
lakes, artificial water reservoirs and canals. Poland is located almost entirely in the
basin area of the Baltic Sea (99.7% of the country’s area) which includes the basins
of the 2 largest rivers, the Vistula and Oder. The remaining 0.3% of the country’s
territory is occupied by rivers falling within the Black Sea (0.2%) and North Sea
(0.1%) basin systems. Most rivers in Poland flow north-west, according to the slope
of the country’s surface.
Almost 88% of Poland’s total area lies in the basin of the two largest Polish rivers:
the Vistula and the Oder. The Vistula river basin (without delta) covers the area of
194.0 thousands km
2 , of which 168.9 thousands km
2 in Poland. The length of the
Vistula is 1022 km, while the average flow is 1044 m
3 . s
−1 . The Oder river basin
covers an area of 119.1 thousands km
2 , of which 106.0 thousands km
2 in Poland.
The length of this river is 840 km (including 726 km in Poland and the border
section 187 km). The average Oder flow is 522 m
3 . s
−1 [2].
Rivers in Poland are fed directly by precipitation and indirectly by snow thaws.
High water levels in Polish rivers occur mainly in spring (February–April). The
second high water level is noted in summer, most often on mountain rivers, as a
result of intensive July rainfall. The lowest water levels take place in early autumn
[3, 4]. On the Baltic coast, high water levels are caused by the storms surges [5].
Most of the lakes in Poland are glacial lakes. Small and shallow lakes predominate among Polish lakes [6]. The largest lakes in terms of area include ´
Sniardwy
(113.4 km
2 ), Mamry (102.8 km
2 ). The deepest lakes include Lake Ha´ ncza with a
depth of 108.5 m, which is located in the Suwałki Lake District. The largest artificial reservoirs include the Solina Reservoir located in a mountain area with a total
capacity of 472.4 million m
3 and the Włocławski Reservoir in a lowland area with a
capacity of 453.6 million m
3 .
In the years 1951–2013 the average annual precipitation for Poland amounted to
618 mm and ranged from 480 mm in Leszno to over 1000 mm in Zakopane [7]. In
general, precipitation in the central lowland of Poland is the lowest [8]. For example,
the average annual precipitation in the period 1951–2015 at the station in Toru´ n
was 527 mm, while in Warsaw 521 mm [9]. The highest rainfall amounts occur in
the summer months (most often in July), while the lowest in the winter months (in
January or February).
The average annual air temperature in Poland in the years 1951–2015 ranges
between 6.4 °C (Suwałki, north-eastern Poland) and 8.9 °C (Słubice, western Poland).
In general, the western part of Poland is warmer than the eastern part. In high parts of
the Tatra Mountains in southern Poland, the average annual air temperature is much
lower and amounts to −0.5 °C at the Kasprowy Wierch station [10].
K. Kubiak-Wójcicka et al.
as waters of the Gulf of Gda´ nsk and ports bordering on territorial sea waters. The
length of the sea border is 440 km, which is 12.5% of the length of the state border
[1]. Almost 50% of the country’s surface is 100–200 m above sea level, while 3%
of the country’s surface is above 500 m amsl. The highest peak in Poland is Rysy
(2499 m amsl).
The most important elements of the hydrographic network in Poland are: rivers,
lakes, artificial water reservoirs and canals. Poland is located almost entirely in the
basin area of the Baltic Sea (99.7% of the country’s area) which includes the basins
of the 2 largest rivers, the Vistula and Oder. The remaining 0.3% of the country’s
territory is occupied by rivers falling within the Black Sea (0.2%) and North Sea
(0.1%) basin systems. Most rivers in Poland flow north-west, according to the slope
of the country’s surface.
Almost 88% of Poland’s total area lies in the basin of the two largest Polish rivers:
the Vistula and the Oder. The Vistula river basin (without delta) covers the area of
194.0 thousands km
2 , of which 168.9 thousands km
2 in Poland. The length of the
Vistula is 1022 km, while the average flow is 1044 m
3 . s
−1 . The Oder river basin
covers an area of 119.1 thousands km
2 , of which 106.0 thousands km
2 in Poland.
The length of this river is 840 km (including 726 km in Poland and the border
section 187 km). The average Oder flow is 522 m
3 . s
−1 [2].
Rivers in Poland are fed directly by precipitation and indirectly by snow thaws.
High water levels in Polish rivers occur mainly in spring (February–April). The
second high water level is noted in summer, most often on mountain rivers, as a
result of intensive July rainfall. The lowest water levels take place in early autumn
[3, 4]. On the Baltic coast, high water levels are caused by the storms surges [5].
Most of the lakes in Poland are glacial lakes. Small and shallow lakes predominate among Polish lakes [6]. The largest lakes in terms of area include ´
Sniardwy
(113.4 km
2 ), Mamry (102.8 km
2 ). The deepest lakes include Lake Ha´ ncza with a
depth of 108.5 m, which is located in the Suwałki Lake District. The largest artificial reservoirs include the Solina Reservoir located in a mountain area with a total
capacity of 472.4 million m
3 and the Włocławski Reservoir in a lowland area with a
capacity of 453.6 million m
3 .
In the years 1951–2013 the average annual precipitation for Poland amounted to
618 mm and ranged from 480 mm in Leszno to over 1000 mm in Zakopane [7]. In
general, precipitation in the central lowland of Poland is the lowest [8]. For example,
the average annual precipitation in the period 1951–2015 at the station in Toru´ n
was 527 mm, while in Warsaw 521 mm [9]. The highest rainfall amounts occur in
the summer months (most often in July), while the lowest in the winter months (in
January or February).
The average annual air temperature in Poland in the years 1951–2015 ranges
between 6.4 °C (Suwałki, north-eastern Poland) and 8.9 °C (Słubice, western Poland).
In general, the western part of Poland is warmer than the eastern part. In high parts of
the Tatra Mountains in southern Poland, the average annual air temperature is much
lower and amounts to −0.5 °C at the Kasprowy Wierch station [10].